# CODEBOOK — Neuroinflammation and Neurodegenerative Disorders Database
## Variable Dictionary | Version 2 | 2026-03-19

## File: Neuroinflammation_Neurodegenerative_Disorders_Database.csv
89 observations x 11 variables

| N | Variable | Type | Description | Unit/Values | Source |
|---|----------|------|-------------|-------------|--------|
| 1 | disorder | Categorical | Neurodegenerative disorder | AD=Alzheimer; PD=Parkinson; MS=Multiple Sclerosis | — |
| 2 | category | Categorical | Data category | Biomarker_CSF; Biomarker_Blood; Neuroimaging_MRI; Neuroimaging_PET; Neuroimaging_SPECT; Clinical_Progression; Epidemiology; Genetics; Drug; Clinical_Trial; Economic_Burden | — |
| 3 | variable_name | Text | Specific variable measured | e.g. IL-6, Hippocampal_Atrophy, CDR, APOE_e4 | — |
| 4 | value_patients | Numeric | Mean or range in patients | Varies by variable (see unit) | Peer-reviewed literature |
| 5 | value_controls | Numeric | Mean or range in healthy controls (NA if not applicable) | Varies; NA if unavailable | Peer-reviewed literature |
| 6 | unit | Text | Measurement unit | pg/mL; mm3; %; scale; OR; M USD; ratio | — |
| 7 | p_value | Numeric | Statistical significance p-value (when available) | 0.0001-0.05; NA if not reported | Primary source |
| 8 | source | Text | Abbreviated bibliographic reference | Author, Year, Journal | PMC/NCBI; Mayo Clinic; MSBase; WHO |
| 9 | year | Integer | Publication year of the source | 2013-2026 | — |
| 10 | notes | Text | Methodological notes, caveats or specifications | Free text | — |
| 11 | confidence_level | Categorical | Evidence confidence level | High (meta-analysis/RCT); Moderate (cohort); Low (case-control/estimate) | GRADE criteria |

## Biomarker Reference Ranges
Cytokines (CSF, pg/mL): IL-6 controls ~2.1, AD ~11.2, PD ~7.8, MS ~9.4
NfL (CSF, pg/mL): controls ~500-800; AD ~1200-2500; PD ~900-1800; MS ~700-2000
GFAP (plasma, pg/mL): controls ~70-100; AD ~250-500; PD ~150-250; MS ~180-300
Amyloid-beta 42 (CSF, pg/mL): controls >1000; AD <500 (decreased)
Total tau (CSF, pg/mL): controls <300; AD >450

## Coding Notes
NA = data not available or not applicable for that disorder/category combination.
For biomarkers with reported ranges, value_patients contains midpoint; notes specifies full range.
Monetary values in USD at year of source publication.